5 1 8 Black . — The Morphology of Riccia Frostii , Aust. 
Bacteria is seen. In the preparation this mass had stained brilliantly with 
the safranin, whereas the mucilaginous content of the neck had taken up 
the gentian violet. That the Bacteria were developing at the expense of 
the sporophyte is seen in the crushed cells beneath the developing colony. 
The cells of the sporophyte or of the surrounding gametophytic tissue are 
not invaded, but the Bacteria as a mass have pushed down or crowded 
the cells of the sporophyte. While it was difficult to distinguish individual 
Bacteria, the colony’ appeared to be composed of small, short rods. The 
entrance of the Bacteria may have been accomplished at the time of 
fertilization. 
Sporogenesis. 
Sporogenesis has been a favoured subject for investigation in many 
Liverworts. Farmer (16), studying the sporogenesis of Pallavicinia decipiens , 
describes a quadripolar spindle in the spore mother-cell, with each of the 
four rays projecting into a lobe of the cell. A note is included on Aneura 
multifida , in which the same condition is observed. In the latter plant 
a centrosphere, but no centrosome, was observed at the extremity of each 
ray. Farmer and Reeves (19), in Pellia epiphylla , Nees, found in dividing 
spores two centrospheres occurring on opposite poles of the nucleus, and 
apparently becoming a factor in the formation of the spindle. No centro- 
some could be demonstrated in the centrosphere. Farmer (17), in 1895, 
published a note on spore formation and karyokinesis in the Hepaticae, 
followed in the same year by a complete report of his results. In the later 
paper (18) various Hepaticae are studied. Farmer found two centrospheres 
in the archesporial divisions of Fossombronia at either end of the nucleus 
which was about to divide. A central body was sometimes distinguished. 
The centrospheres were not apparent in the newly-formed daughter nuclei 
until their walls had been formed. The spore mother-cells become some- 
what four-lobed, but not as strikingly so as in some of the other Junger- 
manniaceae. Centrospheres appear simultaneously at four points on the 
periphery of the spore mother nucleus. The centrospheres become approxi- 
mated in pairs and the first spindle is bipolar. In Pellia epiphylla , Farmer 
records that the centrosphere appears at four points on the periphery of the 
nucleus, and that each contains a small centrosome. Aneura multifida 
exhibits the same type of quadripolar spindle as that found in Fossombronia. 
The quadripolar spindle was not found in Fegatella conica . In germinating 
spores, centrospheres were distinguished. Davis (12), in studying Anthoceros , 
gives a complete history of the divisions in the spore mother-cell, em- 
phasizing particularly the ontogeny of the chloroplast. He describes the 
appearance of threads around the nucleus, which later become the spindle 
fibres. No centrospheres were present. The poles of the spindle were flat, 
slightly convex, but never pointed. Van Hook (43) confirms the absence 
